Bases from bugs and beetles

The staphylinid beetle Stenus comma secretes the alkaloid stenusine (120) which has water spreading properties and thus allows the insect to move easily over the surface of the water. The absolute stereochemistry of the base has not been established, although the gross structure (120) has been synthesised (H. Schildknecht et al., Angew Chem. Intern.Ed., 1975, 14, 427). Australian mealy bugs Cryptolaemus montrouzieri excrete the dialkyIpiperidine (121), and probably also the trans-isomer as well (W.V. 

Brown and B.P. Moore, Austral.J.Chem., 1982, 35, 1255). The resemblance between this structure and those metabolised by fire ants is obvious (see (a) above). 

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